1. Field of the Invention
This invention relates to carbostyril derivatives and a process for preparing the same. More particularly, this invention relates to carbostyril derivatives represented by the formula (I) hereinafter described, the pharmaceutically acceptable acid addition salts thereof, and a process for preparing the same.
2. Description of the Prior Art
It is well known that certain carbostyril derivatives exhibit useful pharmaceutical activities. Representative compounds of this type have been disclosed in Journal of Medical Chemistry, Vol. 15, No. 3, pp. 260-266 (1972), Japanese Patent Publication No. 38789/1971 and Chemical Abstracts, 62, 16212e (1965), etc. However, these prior art references do not teach that the compounds having a [1-acyloxy-2-(unsubstituted or-substituted-amine)]alkyl group at the 5-position and/or an acyloxy group at the 8- and/or 2-position of the carbostyril or 3,4-dihydrocarbostyril moiety possess an excellent .beta.-adrenoreceptor stimulating activity.
The carbostyril and 3,4-dihydrocarbostyril derivatives having a 1-hydroxy-2-(substituted-amino)alkyl group at the 5-position and having a substituent at the 1- and/or 8-position of the carbostyril or 3,4-dihydrocarbostyril moiety and the pharmaceutically acceptable acid addition salts thereof are disclosed in Dutch Patent Application No. 74 16844 and U.S. Pat. Nos. 536,515, filed Dec. 26, 1974, 536,516, filed Dec. 26, 1974, 536,703, filed Dec. 26, 1974, 536,704, filed Dec. 26, 1974 and 536,705, filed Dec. 26, 1974, as having a .beta.-adrenoreceptor stimulating activity and being useful as a therapeutic agent such as a bronchodilator, a peripheral vasodilator, an antihypertensive agent and the like, particularly for treating bronchial asthma.
It has now been found that the carbostyril and 3,4-dihydrocarbostyril derivatives having the formulae (I) also exhibit an excellent .beta.-adrenoreceptor stimulating activity.